Buildings having an exterior façade primarily composed of glass typically comprise a non-loading bearing curtain wall which supports the glass. The curtain wall typically comprises an aluminum frame for supporting the glass comprising a series of mullions for anchoring the frame to the building structure and may also provide a place to abut vertical and/or horizontal building partitions (e.g. walls, floors/ceilings). The mullions provide a space between the building partitions and the glass which may result in undesirable sound transmission between partitioned spaces within the building. The mullion material may also contribute to the transmission of undesirable sound.
Conventional methods for minimizing sound transmission include adding mass to the mullion or adding sound absorbing materials to the mullion, such as filling the mullion with insulation. Another method involves attaching a vibration isolation cover to the mullion face. In another example, a partition wall is cantilevered out to meet the glass and the partition wall is sealed with the glass using caulk.
These methods for minimizing sound transmission often require modifications for each building structure and typically do not provide the desired magnitude decrease in sound transmission. Methods such as cantilevering the partition wall out to meet the glass do not allow for differential movement between the building and the curtain wall system, which can result in tearing of the sealing caulk.
The space provided between the building partitions and the glass can also result in undesirable transmission of fire between partitioned spaces within the building. Wall to ceiling and wall to floor joints can be provided with fire-rated materials to provide a fire stop or break to safeguard against the spread of fire within adjacent spaces of a building. However, the systems used to provide fire-rated materials to wall to ceiling and wall to floor joints often do not work with a curtain wall structure and thus the intersection between the building partition and the glass can present a challenge in terms of preventing the spread of fire between adjacent spaces when a curtain wall is in use.